A cone has______ There are two sides, including______ There is a plane

A cone has There are two sides, including There is a plane

∵ the side of a cone is a curved surface, and the bottom is a plane. A cone is surrounded by two surfaces, one of which is a plane

One plane intersects another, and their intersection is a line_ Line
If a plane intersects another surface, their intersection line is Line

Straight line,

Can the sphere be expanded into a plane figure
I am a student of grade one

No. Gaussian curvature is not zero. No small sphere can be expanded, let alone the whole sphere

Is the sphere surrounded by a plane figure

Of course not. A sphere is a curved surface. There is no plane in it

Can the sphere expand into a plane figure?

Actually, it can't, because the curvature of arc and arc will never become the curvature of straight line and plane
But in the limit content of higher physics, all properties of arc and arc surface can be expressed as a fixed value plus a high-order infinitesimal variable, so it is OK from this definition
In a word, it's impossible in practice, but it's allowed mathematically. But to be honest, theoretical things have no direct significance in real life

Can the sphere be expanded into a plane figure? Why?
It's like a cylinder unfolding into a rectangle

No, if you don't want to, first cut the ball into two hemispheres to see if you can turn the hemisphere into a plane. If it's a cylinder, you can turn it into a plane. But if you think of the ball as infinite, the sphere can be regarded as a plane, just like the earth

Mechanical knowledge: what are the basic methods for finding plane intersection lines?

There are prismatic surface method and prismatic line method

Mechanical knowledge: what is the basic method to find the intersection line of plane and solid?

Edge line method and edge surface method

There are several different types of intersection lines between a plane and a conical surface______ A, 3 kinds of B, 4 kinds of C, 5 kinds of D, 6 kinds of C

The problem of finding intersection line of plane in descriptive geometry
What's the method of doing this? Is it the maximum slope line? Our teacher didn't teach the maximum slope line,

Now that there is a common point a ', find another common point to get the intersection of two planes
In the projection, connect EB, intersection ad is f, and make FF 'vertical XO through XO. Connect e'f' and intersection BB 'to 1'. Because e'f 'is in plane a'd'e', then the straight line e'f 'is in plane, so 1' is in plane a'd'e ', so 1' is also the common point of two planes. Connecting 1'a 'is the solution